[kris396ss]

Hey guys, I have my old trusty 2001 Recon with a metric crap ton of hours on it. when I say this thing is old and beat, I mean it's a modern engineering marvel that it still runs at all.

It actually runs half decent, but I have been having one slight issue with it. I start to hear the valve train ticking away louder than normal, and the bike feels kind of sloppy at the bottom of its power range after 1st gear (going into second, third, fourth...the bottom of the gear range feels sloppier as you go up until you get the RPM's up). AT first I figured the lack of power at the bottom of the gear range was a clutch issue, as the bike is ancient and I'm sure it needs some serious attention in other areas. when I adjusted the valves though, the bike felt WAY better and didn't have the chattery/sluggish feeling at the bottom of the gears. It felt crisp and responsive.

The issue is, after only a few hours I start hearing noise again and the sluggishness returns. I've tried adjusting the valves 3 or 4 times and the same thing happens each time; fine for a little while and then it goes back to the way it was before. It never gets any worse, just doesn't stay as quiet in the valve train or as responsive feeling in the throttle.

I'm thinking it may just be the poly locks are worn out in the rocker and preventing them from holding an adjustment? I know that's a thing on solid roller cam smallblock chevys but is this something you guys have seen on ATV's or am I barking up the wrong tree?

 

[cmanningjr]

its probably the oil pump chain. Very common in Recons...

 

[retro]

The oil pump chain is bound to be shot as @cmanningjr advised. Are you saying that each time you readjust the valves that the lash is found way out of spec again? If that's the case there is excessive wear rates going on, possibly due to little/no oil pressure... due to the worn out oil pump chain skipping over top of the sprockets. As you say... its probably a wonder that it still runs. Its not difficult to fix though.

Its not the locknuts on the adjusters' unless you are finding them loosened up. And ya shouldn't ever run polylocks on any SBC motor, let alone a motor with a SR cam/lifters. Thats 1960s OEM tech.

 

[kris396ss]

I will check the oil pump chain for sure! I have heard a slapping/tapping sound from the crank case at low RPM's at idle as well and it definitely makes sense that could be the issue.


Retro, not sure exactly what you mean. Every smallblock I have ever worked on with aftermarket solid roller valve train used some sort of poly lock set screw/plunger/lock nut setup for valve train adjustment. How else would you make adjustments on a solid lifter setup? What I mean by the wear is I have seen on V8's, over time sometimes either the threads on the adjusters wear out and don't stay locked anymore after cinching it down for the adjustment. The slop allows the screw to back out even after the locknut was torqued tight.

As for your question about lash, that's exactly the issue, the lash is opening up not too long after I adjust it. Not right away, but maybe a couple of hours of riding later I'll start to hear a tap again, power is down slightly and the lash will be slightly out of spec when I check it. Can't hurt to replace the oil pump chain first if that is a common issue, as it definitely could be caused by wear due to lack of oil pressure. Maybe I will mark the adjuster and see if it is actually backing out or if wear is causing the lash to open.

Do you guys think it is worth ordering a timing chain, maybe even clutches while I am in there? I'm always on the fence about going crazy and trying to bring it back to its glory days performance wise or just doing what it needs to stay running since it is an ancient bike. not sure if anything short of a full engine rebuild is going to make it run much better, so maybe i'll just do only what is absolutely needed.

thanks for all the help

 

[retro]

If I were you I would tear that motor down for inspection before making any decisions about parts. Anything you pre-order might be a waste of money if you find out that its far more serious than ya thought. You won't know what is required (or if it's even worth fixing) until ya put eyeballs on everything in the valvetrain, cam bearings included.

Polylocks are self-locking nuts that have nylon plastic inserts molded into them. They were introduced by GM (TRW actually, as an OEM supplier) in the 1960s and were junk. I didn't realize you used that term for all SBC rocker stud locknut types. I never built a motor using stock head castings so I never used standalone locknuts of any kind... put aluminum stud girdles instead, on every 23 degree casting. And I rarely ever bothered with a 23 degree casting unless the track inspector knew how to tell them apart from 17s & 12s. So I'm easy to trick... LOL

 

[shadetree]

keep in mind, if the oil pump chain is bad ?, and you keep adjusting the valves, quite at first, then get loud again ?, its very posb your cam or rocker surfaces are wearing down from lack of oil ?!. I deff would pull the rocker box off, and have a look at your cam lobes, and rocker surfaces !!!.